LUCERNARI.E AND THEIR ALLIES. 83 



165. The Interior intertentacuJur processes demand a little attention in this con- 

 nection, since they are something more than mere intermediate areas between the 

 tentacles. What their precise office is we do not even pretend to suggest, from the 

 knowledge of any established facts ; nor is it necessary that they should have any 

 functional importance, notwithstanding their very marked features. They appear 

 initially as simple, low, conical protrusions {fiy. 58, n) from the areas between the 

 adjacent bases of the tentacles. They are perfectly solid, and include only the 

 gastrophragma and the chondromyoplax (i ) within their limits ; not differin"', 

 therefore, in this respect, from their full-grown condition ( fuj. 55, n). Their 

 innermost wall, at tliis pi-riod, is very thick, fully equal to tliat of the tentacles. 

 Eventually they become more prominent, and, at the same time, connect laterally 

 with each other, forming a network of ridges. This occurs as early as when the 

 umbella is no more than one-eighth of an incli in diameter, and the processes have 

 a slightly pyriform shape. Finally they thicken largely toward the free end, by 

 the enormous development of the chondromyoplax, and become as we have described 

 them (^ 103) in their full grown condition. During the gradual expansion of the 

 chondromyoplax, the gastrophragma proceeds in the inverse way, and finally be- 

 comes excessively thin by tlie time the animal reaches maturity. 



166. The Anchors. — By means of an arrest, or rather retardation, of develop- 

 ment in one specimen, evidently arising from an injury to one side of the umbella, 

 Ave are enal)led to trace the process of the formation of the colletocystigerous laver, 

 and to ])rove, beyond all demands for testimony, that the anchor originally has the 

 proportions and structure of a tentacle. The character of the anchors in a normal 

 condition is illustrated in a figure (Jhj. 32) which we shall describe presently; but 

 we must go back now to a yoimger stage of these bodies, as exhibited by an anclior 

 wliich has developed less rapidly than the others, bc^longing to the same individual. 

 This example {^figs. 30, 31) has all tlie appearances of a tentacle far advanced in 

 development; the globose tip (oc") abounds in nematocysts, and issliarply restricted 

 from the shaft ; the latter is four or five times longer than thick, and its muscles 

 are so strongly developed as to appear like heavy ridges (pc\oc'), as in a full grown, 

 genuine tentacle. The only difference between the tentacle and the anchor is to 

 be found in a slight thickening (oc') of the outer wail of the latter ov(>r the middle 

 third of the shaft, along the distal and lateral portions. This has an oval form. 

 and is studded with coUctoct/sts, scattered in an irregular maimer, just beneath the 

 surface. It is thickest on tlie distal side, and thins out at its edges, to the depth 

 of the wall immediately about it. Its distinctness is due largely to the great 

 development of pigment matter within the nuclei of the cells of the outer wall. 

 There is nothing of the kind as yet on the proximal side, the wall retaining, up to 

 this time, a purely tentacular character (oc'') from one end of the shaft to tlie other. 



167. The next earliest stage after tlie one just described is to be found in the 

 anchor of the youngest Lucernaria that has come under our notice, and described 

 in a previous section (§ 20). In addition to wliat is there recorded we will make 

 some further statemcnits, principally in tlic way of comparison with the previous 

 stage. The main point of difference lies in the relative thickness and extent of 

 the coUetocystic mass, which in the present instance (Jl<j. 123, oc') is considerably 



